<template>
  <div>
    <router-link to="/"
                 tag="div"
                 class="header-ads"
                 v-show="showAbs"
                 :style="opcityStyle"
                 >
      <div class="iconfont header-ads-back">&#xe624;</div>
    </router-link>
    <div class="header-fixed"
         v-show="!showAbs">
      景点详情
      <router-link to="/">
        <div class="iconfont header-fixed-back">&#xe624;</div>
      </router-link>
    </div>
  </div>
</template>

<script>

export default {
  name: 'Header',
  data () {
    return {
      showAbs: true,
      opcityStyle: {
        opacity: 0
      }
    };
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop;
      if (top > 60) {
        let opacity = top / 140;
        opacity = opacity > 1 ? 1 : opacity;
        this.opcityStyle = { opacity };
        this.showAbs = false;
      } else {
        this.showAbs = true;
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll);
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll);
  }
};
</script>

<style lang="stylus" scoped>
@import '~@/assets/styles/varibles.styl'
.header-ads
  position absolute
  left .2rem
  top .2rem
  width .8rem
  height .8rem
  line-height .8rem
  text-align center
  border-radius .4rem
  background rgba(0, 0, 0, 0.8)
  .header-ads-back
    font-size 0.4rem
    color #fff
.header-fixed
  position fixed
  top 0
  left 0
  right 0
  height $headerHeight
  line-height $headerHeight
  text-align center
  color #fff
  background $bgColor
  font-size 0.32rem
  .header-fixed-back
    position absolute
    top 0
    left 0
    width 0.64rem
    text-align center
    font-size 0.4rem
    color #fff
</style>
